Extended STIRAP

The success of this extended STIRAP scheme can be traced to the fact that the basis of the subset of dressed eigenstates of the coupled matter-radiation field is a stationary state representation. In this representation, all couplings are already taken into account via the identity of and the locations of the energy levels. The contribution of the background states to the population transfer process is then limited to effects associated with nonresonant coupling to the field, and if these background states are far off resonance such effects are small. 

V. Kurkal and S. A. Rice. Sensitivity of the extended STIRAP method of selective population transfer to coupling to background states. J. Phys. Chem. B, 105(28) 6488-6494(2001). 

W. Jakubetz. Limitations of STIRAP-like population transfer in extended systems the three-level system embedded in a web of background states. J. Chem. Phys., 137(22) 224312-224327(2012). 

The discretized adiabatic procedure, and its analog with STIRAP, is but one possibility for achieving broadband response of an optical device. An alternative, which we discuss, relies on the analogy between the Jones vector description of an optical beam and the two-state time-dependent Schrodinger equation (TDSE). This equation has two commonly used solutions. One is rapid adiabatic passage (RAP), produced by swept detuning (a chirp), and the other is Rabi oscillations, specifically a pi pulse. The RAP has theoretical connection with STIRAP, but the pi pulses have no such connections. We describe application of a procedure that has been used to extend the traditional pi pulses to broadband excitation. This can accomplish the present goal of PAP, under complementary conditions. 

The topics that mainly concern us in this review have to do with the connections between various coherent optical experiments and LICS. In the next section we discuss the relation between LICS and EIT, examples of which include experiments done in Rb [83,84] and Kr [85]. We then extend the discussion to EIT with structured continua [86, 87]. We proceed by reviewing the use of LICS in the control of population transfer processes [88] the control of PD [89] the production of photo-electrons [90-92] and as a means of steering population transfer processes [93]. We also discuss the connection between LICS and ultrafast methodologies [94] generalized STIRAP techniques [95-97] and coherent population trapping [69,93, 98-101]. 

Generalized STIRAP schemes, including more than three states, for which one state is a continuum have been studied. The bound state tripod system [243, 244] has been extended to a tripod system coupled via a continuum [95], as shown in the left panel of Figure 3.16. In fhis scheme, if is possible to find laser parameters which allow for ionizafion-free partial population transfer between the discrete states within the counter-intuitive pulse order, as shown in the right panel of Figure 3.16. 

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